In a broadband wireless communication system, a base station (BS) apparatus is a system component responsible for communications with a terminal through a radio channel and is a very central device in terms of the radio channel and the access management of the terminal in the wireless communication system.
The data rate required in fourth (4G) generation communication systems, which are the next-generation communication systems, will increasing from units of hundreds of Kbps to several Gbps. To respond to this, the base station is evolving into a structure capable of rapidly processing a number of digital data. In addition, chip sets including Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), and high-speed processors, are advancing to process at the required digital data rates. However, since a single chip set is not able to satisfy the capacity required for new base stations, the structure of the base station is advancing to combine a plurality of chip sets.
FIG. 1 depicts a conventional base station (BS) structure in a broadband wireless communication system.
The base station of FIG. 1 can be divided largely into a digital processor and a radio frequency (RF) processor. The digital processor includes a backplane 110, a processor board 120, a channel card 130, and an intermediate frequency (IF) board 140. The RF processor includes a signal transceiver 150.
The backplane 110 provides signal paths among the components in the digital processor; that is, among the processor board 120, the channel card 130, and the IF board 140. The backplane 110 is of a fixed structure at the design phase of the base station. The structure of the backplane 110 limits the number of the processor boards 120, the channel cards 130, and the IF boards 140 connectable in the base station. That is, the backplane 110 determines the hardware structure of the base station.
The processor board 120 controls functions of the base station. For example, the processor board 120 processes interfacing with an external device and provides a digital signal fed from an upper layer to the channel card 130 to send the digital signal to a corresponding terminal.
The channel card 130 includes a processor 131, a DSP 133, and an FPGA 135. The channel card 130 performs encoding and decoding and modulating and demodulating; that is, functions as a modem. The processor 131 controls functions of the channel card 130. The DSP 133 and the FPGA 135 can be separate physical components but can be considered as the same functional component in the implementation. In some cases, the channel card 130 may include only one of the DSP 133 and the FPGA 135.
The IF board 140 converts the digital signal fed from the channel card 130 to an analog signal of the IF band and provides the analog signal to the signal transceiver 150, and converts an analog signal fed from the signal transceiver 150 to a digital signal and provides the digital signal to the channel card 130. The signal transceiver 150 converts and amplifies the signal fed from the IF board 140 to an RF signal and sends the RF signal over an antenna. The signal transceiver 150 amplifies and converts a signal received on the antenna to an IF signal and provides the IF signal to the IF board 140.
As mentioned above in FIG. 1, the digital processor of the base station is constituted on the board basis to execute the respective functions and the boards exchange the signals via the backplane. Herein, the backplane is formed as the fixed structure at the system design phase. Thus, to install more channel cards over the limited number to increase the processing capacity of the base station, it is necessary to design a new backplane. The channel card can be physically divided into the DSP, the FPGA, and the processor as shown in FIG. 1. When those chips are newly developed, it is required to re-configure the channel card. Besides, as the shape of the channel card changes, the interface also changes. In this situation, the alternation of the whole base station (BS) structure including the backplane may be inevitable. Namely, the conventional BS structure is vulnerable to the shape alternation caused by those reasons.